Conventional die (chip or integrated circuit) testing techniques require first cutting a wafer into chips (dies), then packaging the individual chips in packages. However, the packaged chips increase the volume of the chips. Wafer-level chip scale packaging (WLCSP) technology differs from conventional chip packaging technology. WLCSP technology puts the entire wafer in a package and tests the packaged wafer, and the tested wafer is then cut into dies. The volume of the dies after the package is basically the same as the original size of the dies. Due to the above characteristics of the chip-scale packaging technique, the requirements for die cutting are more stringent. In the current product inspection process, it is necessary to pick up packaged dies from different locations on the wafer to perform the test (including, but not limited to testing the quality of the side and back side of the packaged dies).
In the prior art, the selection of the dies is carried out using a manual selection approach, i.e., manually picking up a die to be tested using a vacuum needle may have the following problems. Firstly, a to-be-tested die is manually picked up, the vacuum needle may be in contact with neighboring dies, resulting in damage to the to-be-tested die and the neighboring dies. Secondly, the manually selection of a die is a random process that may cause wrinkles to the dicing tape, which, in turn, results in the failure of an incomplete scanning in an automatic optical detector test, and virtually increases the risk of releasing defective dies.
Thus, there is a need for an improved apparatus and method for automatic sorting semiconductor dies.